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Replace a compiler-specific approach to determining the presence of a getDecl() member function with one that does not require compiler-specific workarounds; NFC. 

llvm-svn: 261872
This commit is contained in:
Aaron Ballman 2016-02-25 15:14:09 +00:00
parent 74a7bb39a2
commit 0eb1d7bca0
1 changed files with 14 additions and 25 deletions
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39
clang/include/clang/ASTMatchers/ASTMatchersInternal.h
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@ -569,32 +569,21 @@ bool matchesFirstInPointerRange(const MatcherT &Matcher, IteratorT Start,
return false;
}
// Metafunction to determine if type T has a member called
// getDecl.
#if defined(_MSC_VER) && !defined(__clang__)
// For MSVC, we use a weird nonstandard __if_exists statement, as it
// is not standards-conformant enough to properly compile the standard
// code below. (At least up through MSVC 2015 require this workaround)
template <typename T> struct has_getDecl {
__if_exists(T::getDecl) {
enum { value = 1 };
}
__if_not_exists(T::getDecl) {
enum { value = 0 };
}
// Metafunction to determine if type T has a member called getDecl.
template <typename Ty>
class has_getDecl {
typedef char yes[1];
typedef char no[2];
template <typename Inner>
static yes& test(Inner *I, decltype(I->getDecl()) * = nullptr);
template <typename>
static no& test(...);
public:
static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
};
#else
// There is a default template inheriting from "false_type". Then, a
// partial specialization inherits from "true_type". However, this
// specialization will only exist when the call to getDecl() isn't an
// error -- it vanishes by SFINAE when the member doesn't exist.
template <typename> struct type_sink_to_void { typedef void type; };
template <typename T, typename = void> struct has_getDecl : std::false_type {};
template <typename T>
struct has_getDecl<
T, typename type_sink_to_void<decltype(std::declval<T>().getDecl())>::type>
: std::true_type {};
#endif
/// \brief Matches overloaded operators with a specific name.
///